Character Models LOD

ncav

Hey guys

I was just curious as to what are generally accepted workflows when working with character models requiring multiple level's of detail, especially with regards to retaining the same uv sets. Any nudges in the right direction would be appreciated.

Cheers

CheeseOnToast

Basically, try to avoid anything that makes the silhouette drastically change between two neighbouring LODs. Deleting edges on UV border is bad news too. Tangent space normal maps can be surprisingly robust at a distance, but still try to avoid introducing really big changes in vertex normal direction. As you get to the really low (distant) LODs, you can get a lot looser with these guidelines.

Try collapsing edge rings/ single edges rather than outright deleting edge loops. That will average out the vertex positions, so you won't see as much of a jump between LODs. Make sure you preserve enough at joints for animation to still work. So if you're reducing an arm, for example, take away edges from mid bicep and mid forearm more aggressively than from around the shoulder and elbow.

As for how much to reduce, generally go somewhere between two thirds to a half of the polycount of the next highest LOD. For example, a 9000 poly mesh at LOD 0, 5000 at LOD 1, 2500 at LOD 2 etc. It really depends on the game though.

ncav

Sweet, cheers for the advice dude , I'll give it a go.

ZacD

I've also heard of games sometimes using different textures and materials for LOD0 and LOD1-3, I don't know how common that is though.

CheeseOnToast

I've not run into LODs using different textures so far (other than mip maps). It's fairly common for the shader to be swapped out for a cheaper/simpler version on lower LODs though.